High speed stock feeder

ABSTRACT

High-speed strip-feeding apparatus having two feedheads that are reciprocated by two air motor means respectively. A work-clamping device is operatively mounted on each feedhead and is actuated by an additional air motor means. All of said air motor means are adapted to be sequentially controlled by a fluid valve means that is operative in one condition so that at least some of said air motor means may receive fluid pressure, and operative in another condition so that at least some of said air motor means are connected to exhaust means whereby said feedheads are alternately actuated so as to respectively advance successive lengths of the strip to be fed into a work station.

United States Patent [72] Inventor Albert W. Scribner 6 Country Club Road, Darien, Conn. 06820 [21] Appl. No. 37,447 [22] Filed May 15, 1970 [Z3] Continuation of Ser. No. 648,345, June 23,

1967, abandoned [45] Patented June 8,1971

[54] HIGH SPEED STOCK FEEDER 50 Claims, 19 Drawing Figs.

[52] U.S.Cl 83/225, 83/247, 83/257, 83/277, 226/112, 226/162 [51] Int. Cl 826d 5/20 [50] Field of Search 83/225, 247, 257, 277; 226/1 12, 162

[56] Relerences Cited UNITED STATES PATENTS 3,038,645 6/1962 Nordlof 226/162X 3,123,270 3/1964 Olson 226/162X 3,172,323 3/1965 Burd 83/225 3,296,907 1/1967 Edelman 83/277X 3,329,327 7/1967 Scribner 226/162X 3,410,161 11/1968 Roch 83/277X Primary Examiner-Frank T. Yost ABSTRACT: High-speed strip-feeding apparatus having two feedheads that are reciprocated by two air motor means respectively. A work-clamping device is operatively mounted on each feedhead and is actuated by an additional air motor means. All of said air motor means are adapted to be sequentially controlled by a fluid valve means that is operative in one condition so that at least some of said air motor means may receive fluid pressure, and operative in another condition so that at least some of said air motor means are connected to exhaust means whereby said feedheads are alternately actuated so as to respectively advance successive lengths of the strip to be fed into a work station.

HIGH SPEED STOCK FEEDER This is a continuation of application Ser. No. 648,345 filed June 23, I967, now abandoned.

This invention relates to an improved high-speed stockfeeding apparatus for punch presses and the like. More particularly the invention relates to improved duplex stock-feeding device that utilizes a novel fluid-actuating and control means.

Newer types of punch presses and similar equipment are being designed to afford higher and higher cyclic operating speeds. Press speeds of over 600 cycles per minute are now common however such operating rates make more difficult the task of accurately and efficiently advancing the strip stock into the press work station. Prior attempts to provide a highspeed stock feeder have for the most part resulted in relatively heavy, cumbersome and/or expensive apparatus. The instant invention contemplates overcoming these difficulties by utilizing a particular combination of fluid-operated components and controls therefore in a stock feeder so as to render the device capable of more efficiently producing a high-speed intermittent advancing movement of the strip stock to be fed into a machine work station.

The primary object of the instant invention is to provide a novel high-speed stock feeder that is constructed so as to be relatively simple, light, inexpensive and easy to install.

Another object of the invention is to provide an improved high-speed stock feeder wherein a novel combination of fluidoperated motors for operating the stock-gripping, stockclamping and stock-advancing means associated with the feeder.

Another object of the invention is to provide a novel fluid control circuit andrelated means for more efficiently controlling the operation ofa double-acting stock-feeding device.

Another object of the invention is to provide an improved control-valving arrangement for high-speed stock-feeding devices whereby only a minimum of moving elements are required.

A further object of the invention is to provide a novel highspeed stock feeder wherein a novel motion-translating means is arranged so as to be actuated by the reciprocating movement of an associated press ram so as to intermittently operate the fluid-valving means that controls the various fluid motors in said feeder.

Other objects will become apparent as the disclosure progresses.

FIG. 1 is a plan view in partial section of the principal structure of one embodiment of the instant stock feeder.

FIG. 2 is a sectional view taken along section line 2-2 of FIG. 1.

FIG. 3 is a sectional view taken along section line 33 of FIG. 1.

FIG. 4 is a sectional view taken along section line 44 of FIG. 1.

FIG. 5 is a circuit diagram illustrating the fluid control means for the apparatus of FIGS. l4.

FIG. 6 is an axial sectional view of one of the three-way valving units used in the circuitry of FIG. 5.

FIG. 7 is a fragmentary axial sectional view of the exhaust portion of the valve illustrated in FIG. 6.

FIG. 8 is a diagrammatic-type view of the valve-actuating means that is driven by the press crankshaft.

FIG. 9 is a timing diagram for the apparatus of FIGS. 1-8.

FIG. 10 is a plan view in partial section of the principal structure of a second embodiment of the instant feeder.

FIG. 11 is a sectional view taken along section line 11-11 of FIG. 10.

FIG. 12 is a sectional view taken along section line I2-I2 of FIG. 10.

FIG. 13 is a sectional view taken along section line 13-13 of FIG. 10.

FIG. 14 is a front elevational view of a portion of the FIG. 10 apparatus.

FIG. 15 is a circuit diagram illustrating the fluid control means for the apparatus of FIGS. 10l4.

FIG. 16 is a diagrammatic view illustrating the nature of the valve-actuating cam grooves.

FIG. 17 is a sectional view taken along the diagrammatic section line 17-17 of FIG. 16.

FIG. 18 is a timing diagram for the apparatus of FIGS. 10- 17.

FIG. 19 is a fragmentary elevational view illustrating a modified valve actuating means for the circuit diagram of FIG. 15.

Referring to FIGS. l4 there is shown a pneumatically actuated duplex or double-acting stock-feeding arrangement comprising a frame 10 that includes a forward cylinder block 11 and a rearward cylinder block 12 which are rigidly interconnected by a pair of side rails 13 and 14 that are fastened to the sides of said blocks by any suitable means such as screws 15. A center rod 16 is threadedly connected at each of said blocks. A cylinder 17 is formed in block 11 and a piston 20 slidably mounted therein, piston 20 being fastened to a connecting rod 21. Rod 21 extends through a suitable aperture formed in the cylinder-closing end plate 22 that is sealingly secured to the end of the block 11 by any suitable fastening means such as screws 23. The'outer end of piston rod 21 is secured to a first feed head 24 that is slidably mounted on the side rail 13 and the center rod 16 as is best shown in FIGS. 1 and 4. The feed head 24 comprises a lower body portion 25 in which is formed a cylinder 26, the top of said cylinder 26 being closed by an upper plate 27 that is sealingly secured to said body portion 25 by an suitable fastening means. A double-acting piston 30, FIG. 2, is slidably mounted in cylinder 26 and is fastened to a piston rod 31 that extends upwardly through a suitable aperture in cover plate 27 and has secured to its upper end, as by any suitable means 33a, FIG. 2 a laterally inwardly extending stock-gripping bar 32, constituting an open throated stock-gripping means. The portion of cylinder 26 above the piston 30 is pneumatically coupled through a port 33 to a flexible control tube or line 34 while the portion of the'cylinder 26 below said piston 30 is pneumatically coupled through a port 35 to a flexible control tube or line 36. The rearward or right end of cylinder 17 as seen in FIGS. 1 and 2 is pneumatically coupled through a port 40 to a flexible control tube or line 41 while the forward end of cylinder 17 is pneumatically coupled through a port 42 to a flexible control tube or line 43.

The rearward cylinder block 12 is provided with a cylinder 47, a piston 50, a piston rod 51, an end plate 52 a fastening means similar to 23 and a feedhead 53 that are constructed and arranged the same as the above-described corresponding parts associated with the forward block 11. The outer end of piston rod 51 is secured to a second feedhead 53 that is slidably mounted on the side rail 14 and center rod 16. The feedhead 53, the cylinder 54, end cover plate 55, piston 56, piston rod 57 and clamp bar 60 are also all constructed and arranged in a manner similar to the corresponding elements associated with the above-described feedhead 24. The piston 56 however is a single acting piston, the portion of said cylinder 54 below said piston 56 being vented through the port 61 and containing a compression spring 62 that biases the piston 56 upwardly. The portion of cylinder 54 above piston 56 is pneumatically coupled through a port 63 to a flexible control tube or line 64. The forward or left end of cylinder 47 as seen in FIGS. I and 3 is pneumatically coupled through a port 65 to a flexible control tube or line 66 while the rearward end of cylinder 47 is pneumatically coupled through a port 67 to a flexible control tube or line 70.

The first fluid motor that is effectively defined by elements 17, 20 and 21, the second fluid motor that is effectively defined by elements 26, 30 and 31, the third fluid motor that is effectively defined by elements 47, 50 and 51, and the fourth fluid motor that is effectively defined by elements 54, 56 and 57 are all provided with the necessary O-ring or other similar means for the sliding actions involved.

The feedheads 24 and 53, which are mounted for movement in side-by-side relation, are reciprocally actuated by said first and third fluid motors, respectively, in indexing and stockfeeding direction 71 and 72, FIG. 1, and said stock-gripping bars 32 and 60 are moved between stock-gripping and stockreleasing positions by said second and fourth fluid motors. The forward limits of movement of feedheads 24 and 53 are each determined by engagement thereof with the said end plate 22 on block 11 while the rearward limits of movement of said feedheads are each determined by engagement thereof with a common stop member 73 that thrcadedly engages a sleeve 74 that is pinned as at 75 to said center rod 16. The provision of additional holes 76 formed in rod 16 affords a coarse adjustment for the stroke length of feedheads 24 and 53 while the threaded coupling between stop member 73 and sleeve 74 affords a fine feedhcad stroke adjustment, the locknut 77 providing means to lock the stop member 73 and sleeve 74 in adjusted position. The feedheads 24 and 53 are thus reciprocally actuated in side-by-side relation and between common stop means 22 and 73. Any suitable adjustable stock-guiding means 80 may be provided at the rearward end of the feeder frame while a pair of bores 81 or other suitable means are provided at the forward end of frame 10 for facilitating the mounting of the instant stock feeder in fixed relation to the associated punch press or other machine.

In FIGS. 58 there is shown a fluid control circuit, a control valve means, and a valve-operating means. Referring first to the circuit diagram of FIG. 5 there is diagrammatically illustrated the above noted first, second, third and fourth fluid motors and the control circuitry thereof. A source 85 of fluid pressure is connected directly by line 86 and said line 66 to the forward end of cylinder 47, and is connected directly by line 86 and said line 34 to the upper end of the clamp cylinder 26. Further said source 85 is connected directly by line 86 and said line 41 to the rearward end of cylinder 17 and also directly by lines 86 and 87 to the supply or inlet lines 90 and 91 of two three-way control valves 92 and 93 respectively. The three-way valves 92 and 93 are provided with output lines 94 and 95 and are each adapted to be actuated in timed relation by means ofa rotary cam 96. Each valve is operative in its normal condition illustrated in FIG. 5 to connect its output line to exhaust and is operative in its actuated condition to connect its output line to the fluid pressure from said lines 90 and 91 as will be more fully discussed in connection with FIGS. 6 and 7. The output line 94 is connected by said line 36 to the lower end of said clamp cylinder 26 and by said line 64 to the upper end of said clamp cylinder 54. The output line 95 of valve 93 is connected by said line 70 to the rearward end of the cylinder 47 and by said line 43 to the forward end of cylinder 17. Suitable air restriction means 100 and 101 are provided in lines 70 and 43 respectively so as to control the rate offluid flow to and from said cylinders 47 and 17.

Referring now to FIGS. 6 and 7 the construction and arrangement for one of the two similar three-way valves 92, 93 used here will be described. The valve 92 comprises a body 110 having a cylinder 111 formed therein which is pneumatically connected through a suitable port 112 to said pressure inlet line 90. The upper end of cylinder 111 is closed by means of a cap 113 and a gasket 114 that are suitably secured to said body 110. A valve member 115 is slidably mounted in cylinder 111, and comprises a head 116 which has an effective crosssectional area that is slightly less than the corresponding effective cross-sectional area of said cylinder 111, and which has a radially outer upper face valving portion 117 that is adapted to normally seat against the adjacent lower surface of said cap 113. A valve stem 120 is connected at its lower end for limited axial sliding movement on and relative to the valve head 116, and extends upwardly through a suitable aperture formed in said cap 113. The lower reduced end 121 of the valve item 120 extends through a suitable aperture formed through the valve head 116 and its upper boss 122 and is provided with a suitable fastening nut 123 or the like at its lowermost end. The cap 113 is formed with a lower cylindrical recess 125 that is pneumatically connected by a port 126 to the said flexible control tube or line 94. Cap 113 is also formed with an exhaust port 127 FIG. 7, that normally communicates with said recess 125 in cap 113.

As will be apparent the fluid pressure that is always present in the lower end of valve cylinder 111 will continuously bias the movable valve to the said normal upper position illustrated in FIG. 6. In this normal condition of the valve 92 the said valve outlet or control line 94 is connected to said exhaust port 127 and hence fluid pressure in line 94 will be normally vented or exhausted to the atmosphere. When'the valve stem is axially displaced downwardly the shoulder 130, FIG. 7, on said stem first closes the adjacent end of the exhaust port and then engages the said boss 122 on the valve head 116, the reduced lower end 121 of the valve stem during this much of its downward movement simple moving axially through and relative to the still stationary valve head 116. Continued downward movement of valve stem 120 will now cause the valve head 116 to unseat and move downwardly with the valve stem, as is illustrated by the dotted lines in FIG. 6, so as to thereby pneumatically connect the fluid pressure in the lower portion of said cylinder 111 to said valve outlet line 94 through said recess and port 126. Under these conditions fluid pressure will be applied to line 94 while the valve exhaust port 127 is closed. When the valve stem is allowed to move upwardly the fluid pressure in cylinder 111 will displace the valve member 115 to its normal upper position illustrated in FIG. 6. During this upward movement the valve head 116 will first be arrested in its said normal seated position, thereby sealing off the lower portion of cylinder 111 from the outlet line 94. Continued upward movement of the valve stem will cause the stem shoulder 130 to uncover the exhaust port 127 so that fluid pressure in line 94 may be exhausted. If desired a suitable light spring 131, FIG. 6 may be provided for lightly biasing the valve head 116 upwardly relative to the reduced portion of the valve stem 120. It will be understood that the construction and operation of valve 93 corresponds to that just described for valve 90. As will be apparent the valve 92 controls the operation of the fluid motors that actuate the two instant stock-gripping means while the valve 93 controls the operation of the two fluid motors that actuates the feedheads 24 and 53.

The outer ends of the respective valve stems of valves 92 and 93 are provided with well-known conventional-type rollers that are diagrammatically illustrated at and 141 respectively in FIG. 6. These rollers cooperate with the peripheral surface of said rotary cam 96 so that the valves 92 and 93 may be actuated in timed relation with the operation of the associated press. The cam 96 has two arcuate peripheral camming surfaces 96a and 96b, surface 960 being substantially circular in contour and extending substantially halfway around the cam periphery while surface 96b is also substantially circular in contour and extends the remaining way around the cam periphery. The surface 96a has a shorter radi al dimension than that for surface 96b. Interconnecting said surfaces 96a and 961: are inclined surfaces 960 and 96d. The means for driving the cam 96 functions to cause the latter to rotate once for each two rotations of the main crankshaft of the press and comprises a shaft 142, FIG. 8, on which cam 96 is secured and which is rotatably supported on the press frame by any suitable means such as brackets 143 and 144. The shaft 142 is coupled through bevel gears 145, 146 to a shaft 147 that is rotatably supported by any suitable means such as brackets 143 and 150 on the press frame. The gear 145 is effectively twice as large as gear 146 and hence the gear ratio between shafts 147 and 142 is two to one. The shaft 147 is adapted to be driven by the main crankshaft 151 of the press through bevel gears 152, 153. As the cam 96 is thus rotated as indicated by arrow 154 of FIG. 5 the inclined cam surface 960 will first depress the stem of the stock-gripping control valve 92 so that the fluid motors for the stock clamp bars 32 and 60 first set said stock-gripping means to their operative positions and thereafter said inclined surface 960 will depress the valve stem of the feedhead-actuating control valve 93 so that the fluid motors for actuating said feedheads 24, 53 will then be operated. Subsequently the inclined surface 96d will permit said valve stems for valves 92 and 93 to be sequentially restored to their normal positions so that the said stockgripping means and the said feedheads 24 and 53 are corresponding and sequentially actuated.

A description of the overall operation of the instant stockfeeding device will now he made, Referring initially to the timing diagram of FIG. 9 the arrows 160 and 161 indicate the downwardly and upwardly moving halves respectively, of the motion of the press ram during a first cycle I of operation. Arrows 162 and 163 correspondingly denote the downward and upward motions of the ram during its next following cycle ll of operation. During these two ram cycles the cam 96 will be rotated only once. The dotted line 164 of FIG. 9 indicates the periods when the press punch is in engagement with the stock material (these periods being represented by those portions of arrows 160, 161, 162 and 163 that are below said line 164). In the normal upper rest position of the press ram the rotary cam 96 will be in a position similar to that shown in FIG. 5 wherein both valve stem rollers 140, 141 are in contact with the radially shorter cam surface 96a so that both valves 92 and 93 are in their normal positions wherein their outlet lines 94 and 95 are connected to exhaust, Under these valve conditions the condition of the FIG. 5 fluid circuit and associated fluid motors will be as follows. The piston and feedhead 24 will be moved by the said continuous fluid-biasing pressure in the rearward end of cylinder 17 in a feed direction 72 so that feedhead 24 engages the main block plate 22. During this movement the stock-gripping bar 32 on feedhead 24 will be held in a stock-gripping position by reason of the action of the continuous fluid-biasing pressure in the upper end of said feedhead cylinder 26. In similar fashion the piston 50 and feedhead 53 will be moved by the said continuous fluid-biasing pressure in the forward end of cylinder 47 in an indexing direction 71 so that said feedhead 53 engages the adjustable stop 73. During this movement the stock-gripping bar 60 on feedhead 53 will be held in a stock-releasing position by the spring 62. Thus the feedhead 24 is normally held in a forward stock-gripping position while the feedhead 53 is normally held in a rearward stockreleasing position. When the punch press is set in operation the press crankshaft will rotatably drive the came 96 in the direction indicated by arrow 154, FIG. 5, at a two-to-one gear ratio through the gearing described in connection with FIG. 8. As the cam 96 thus rotates its inclined surface 960 will, at a time t, in the timing diagram of FIG. 9, first depress the stem of stock-gripping control valve 92 so that fluid pressure is admitted to valve outlet line 94 which thereby causes piston 30 to be moved upwardly and piston 56 to be moved downwardly thus respectively moving the stockgripping means on feedhead 24 to a stock-releasing position and the stock-gripping means on feedhead 53 to a stockgripping position. Shortly thereafter at a time I, in the timing diagram of FIG. 9, said inclined cam surface 960 will depress the stem of the feedhead actuating valve 93 so that fluid pressure is admitted to valve outlet line 95 which thereby causes piston 20 and feedhead 24 to be moved in direction 71 and piston 50 and feedhead 53 to be moved in a feed direction 72. During this described cycle I of operation of the punch press the stock-gripping means on the feedheads are set at a time I, just after said press punch has engaged the stock and the feedhead-actuating motors are actuated at a time t, just after said press punch has withdrawn from engagement with said stock. Thus during cycle'l feedhead 24 is actuated through an indexing stroke while feedhead 53 is simultaneously actuated through a stock-feeding stroke so as to advance the stock by a predetermined length into the work station of the press.

During the next cycle 11 of the press the continued rotation of cam 96 will cause, at a time I in the timing diagram of FIG. 9, the inclined surface 96d thereof to first allow the stem of stock-gripping control valve 92 to be restored to its said normal position so that the outlet line 94 thereof is connected to exhaust which thereby allows the said downwardly biased piston 30 and the associated stock-gripping means on the feedhead 24 to be moved to a stock-gripping position while the upwardly spring-biased piston 56 and associated stockgripping means on the feedhead 53 are moved to a stockreleasing position. Shortly thereafter, at a time t, in the timing diagram of FIG. 9, the inclined surface 96d of the rotating cam will allow the valve stem of the feedhead-actuating control valve 93 to be restored to its said normal position so that the outlet line 95 thereof is connected to exhaust which thereby allows said forwardly biased piston 20 and feedhead 24 to be moved in a feed direction 72 and said rearwardly biased piston 50 and feedhead 53 to be moved in an index direction 71. During this cycle ll of operation of the press the stockgripping means on the feedheads are again set at a time just after the press punch has engaged the stock and the feedheads are again actuated at a time 1 just after the said punch has been withdrawn from engagement with said stock. Thus during cycle ll feedhead 53 is actuated through an indexing stroke while feedhead 24 is simultaneously actuated through a stockfeeding stroke so as to advance a second equal length of stock into the work station of the press. It will be apparent that by utilizing two feedheads substantially all of the time during each press cycle that the punch is out of engagement with the stock may be used for the stock-advancing movement of one of said feedheads. Further the stock-gripping means are already set and ready for the next stock-feeding stroke when the punch is withdrawn from said stock. Under these conditions the successive stock-advancing movements alternately produced by the feedheads 24 and 53 may occur at a very rapid rate so as to efficiently and accurately feed stock into the work station.

Referring to FIGS. 10l9 an alternate embodiment of a duplex-type feeder and control arrangement therefor is illustrated. In FIGS. 10-13 there is shown a feeder construction that includes a frame comprising a forward body block 171, a rearward body block 172, and a pair of side rails 173 and 174 that are fixedly secured to the sides of said blocks by any suitable means such as screws 175. A stop block 176 is fixedly mounted to rails 173, 174 as by means of screws 177, at a location approximately midway between said blocks 171 and 172. Slidably mounted on rails 173, 174 between body block 171 and stop block 176 is a first feedhead 180 that is connected to and adapted to be actuated in indexing and stockfeeding directions 181 and 182 respectively by a first fluid motor that is effectively defined by a cylinder 183, a piston 184, a piston rod 185 and fluid flow ports 186, 187 at opposite ends of said cylinder 181 that are constructed and arranged in the same manner as that effectively defined by 17, 20, 21 and 42, 40 etc., FIGS. 1-4, for similarly actuating said feedhead 24. Slidably mounted on rails 173, 174 between the body block 172 and the stop block 176 is a second feedhead 190 that is connected to and adapted to be actuated in said directions 181, 182 by a second fluid motor that is effectively defined by a cylinder 191, a piston 192, a piston rod 193, and fluid flow ports 194, at opposite ends of said cylinder 191 that are constructed and arranged in the same manner as that effectively defined by 47, 50 51 and 65 67, FIGS. 14 for similarly actuating said feedhead 53. The forward limit of movement of feedhead 180 is determined by engagement of the latter with the end plate 196 secured to the block 171 while the rearward limit of movement thereof is determined by engagement with an adjustable stop bolt 197 which is threadedly fastened to stopblock 176 and which is locked in adjusted position by a locknut 200. In similar fashion the rearward limit of movement of feedhead 190 is determined by engagement of the latter with the end plate 199 secured to said block 172 while the forward limit of movement thereof is determined by engagement with an adjustable stop bolt 202 which is also threadedly engaged with said stopblock 176 and which may be locked in adjusted position by locknut 203. For any given stock-feeding operation the stop bolts 197 and 202 are adjusted so that feedheads 180 and 190, which are arranged in tandem, have feed strokes of equal length.

Each of the feedheads 180 and 190 carries a stock-gripping means that is adapted to be actuated by two similar fluid motors. Considering first the feedhead I80 illustrated in FIGS. l0, l1 and 12, a body 210 is provided with cylinders 211 and 212 in which are slidably mounted two pistons 213 and 214 that are connected to two piston rods 215 and 216 respectively. Rods 215 216 extend upwardly through suitable apertures in a cover plate 217 that is secured by any suitable means to said body 210. The upper ends of piston rods 215, 216 are respectively connected by any suitable means to the end portions of a stock-gripping bar 220 that is adapted to be moved between stock-gripping and stock-releasing positions. The upper ends of cylinders 211 and 212 are each connected through bores 221 and 222 with a flexible control tube or line 223 as is best seen in FIG. 12. The lower ends of cylinders 211 and 212 are each connected by bores 224 and 225 with a flexible control tube or line 226.

The feedhead 190 comprises a body 230, FIG. 13, in which is formed two cylinders 231 and 232 in which are slidably mounted two pistons 233 and 234 that are connected to piston rods 235 and 236 respectively. The rods 235 and 236 extend upwardly through appropriate apertures in a cover plate 240 which effectively closes the upper ends of said cylinder 231, 232 and which is secured by any suitable means to the upper face of body 230. The upper ends of piston rods 235 and 236 are respectively connected to the end portions of a stockgripping bar 241 that is adapted to be moved between stockgripping and stock-releasing positions. Springs 242 and 243 respectively bias pistons 233, 234 and the bar 241 to stockreleasing positions. The upper portions of cylinders 231 and 232 are each connected by bores 244 and 245 to a flexible control tube or line 246, while the lower portions of cylinders 231, 232 are vented to atmosphere by ports 247 and 248 respectively.

As before mentioned any suitable sealing means, such as rings or the like may be used for the various sliding pistoncylinder arrangements. Any suitable stock-guiding means 250 may be provided in the rearward block 172 while suitable feeder mounting holes 251 may be provided in the forward block 171. As illustrated in FIG. 14 the side rails 173 and 174 are provided with extra sets of holes 252 to accommodate the mounting screws 175 for the block 172, and also with extra sets of holes 253 to accommodate the mounting screws 177 for the stop block 176. The spacing 254 between the sets of holes 252 is twice as long as the corresponding spacing 255 between the sets of holes 253. By this arrangement the blocks 172 and 176 may be adjusted relative to the fixed block 171 so as to thereby define a coarse adjustment for the stroke lengths of feedheads 180, 190, while said stop nuts 197 and 202 provide a fine adjustment means for varying the stroke lengths of said feedheads. t

Referring now to FIGS. 15, 16 and 17 a pneumatic circuit for the instant feeder is shown together with a control valve and a valve-actuating means. Referring first to the circuit diagram of FIG. 15 the various fluid motors described in connection with FIGS. 13 are interconnected as follows. A source 260 of fluid pressure is connected directly by line 261 and said line 262 to the said port 194 at the forward end of cylinder 191, and directly by lines 261 and 263 to the upper end of cylinders 211 and 212 of feedhead 180. (only feedhead cylinders 211 and 231 and their related elements have been illustrated in FIG. however it will be understood that the corresponding circuit connections exist, through the abovedescribed FIGS. 1013 apparatus, for the cylinders 212 and 232 and their related elements.) The fluid pressure source 260 is also directly connected by lines 261 and 264 to the said port 187 at the rearward end of the cylinder 183, and directly by line 265 to the supply inlet to the three-way valve 266, the latter being constructed and arranged in the same manner as that previously described in connection with FIGS. 6 and 7 for valve 92. The output or control line 267 of valve 266 is connected to the lower ends of said cylinders 211 and 212 through line 270 and said line 226, and to the upper ends of cylinders 231 and 232 through said lines 270 and 246. The

output line 267 of valve 266 is also connected to said port 186 at the forward end of cylinder 183 through a line 271, and to the said port 195 at the rearward end of said cylinder 191 through a line 272. A fluid flow restriction means 273 is provided in the lines to said ports 186 and 195 so as to control the rates at which fluid may flow to and from said cylinders 183 and 191.

Not only is the circuit in FIG. 15 different from that in FIG. 5, the means for actuating the single three-way valve 266 is also different. The valve-actuating means here comprises a camming means that is operated directly by the press ram so that the FIG. 8 gearing connections etc. to the press frame are all but eliminated. In this way the FIGS. 1013 stock feeder may be readily set up by a relatively simple direct connection between the press ram and the instant valve-actuating means. Referring again to FIG. 15 there is shown a cam 280 having a periphery contoured in a manner similar to that described above for cam 96 of FIG. 5 and cooperating with the roller 281 of the valve stem for said valve 266. Cam 280 is fixed to a shaft 282 that is rotatably mounted in a bracket 283 which may be secured on either the press or on the said stock feeder frame. Suitable thrust bearing means 284 and 285 are provided for shaft 282. The upper end of said shaft 282 is formed with a set of four serially interconnected similar spiral-type grooves 286, 287, 288, 289 as are illustrated in developed plane form in FIG. 16. Cooperating with the grooved upper portion of shaft 282 is a collar 290 that is connected by any suitable fastening means to a bracket 291 that is secured by any suitable means to the adjacent side of the press ram 292. The collar 290 is provided with two similar diametrally opposed cam follower units 293 and 294. In that each of said units is constructed and operates in a similar manner only a detailed description of one of said units need be made here. The unit 293 comprises a tubular type cap 295 which is threadedly fastened to said collar 290 and which contains a cam follower pin 296 that is biased radially inwardly towards the axis ofshaft 282 by means ofa suitable spring 297. The inwardly biased cam follower pin 300 for the said unit 294 is coaxially disposed relative to said cam follower pin 296. The inner ends of these diametrally opposed pins are adapted to cooperate with the four equally peripherally spaced and symmetrically located grooves 286, 287, 288 and 289. As will be apparent from FIG. 16 each of said grooves extends around the periphery of shaft 282.

As the collar 290 is axially reciprocated by the reciprocating motion 301 of of the press ram the cam follower pins 296 and 300 will, in cooperating with said grooves, cause shaft 282 to be intermittently rotated through successive 90 increments of movement. Means are provided to insure that the said intermittent rotary movement of the shaft 282 is always in one rotative direction. Such means are provided by contouring the bottom of said grooves in a manner that will now be described. In that each of said spiral-type grooves is correspondingly contoured a description of just groove 288 will suffice here. Referring to FIGS. 16 and 17, (the latter being a sectional view diagrammatically taken along a section line 17-17 of FIG. 16), there is shown a stepdown shoulder 302 at the junction of the end 2870 of the groove 287 and the beginning 288a of groove 288. The bottom of the central portion 288!) of groove 288 is slightly inclined until it reaches at the end 2881: of said groove 288 another stepdown shoulder 303 at the deep-ended beginning 2890 of the next groove 289. As will be apparent from the arrows in FIGS. 16 and 17, which denote the movement of the cam follower pins 296, 300 through said grooves, that as each of these radially inwardly biased pins moves from one groove to the next it will drop successively down off the shoulders 302, 303, 304 and 305 to the deeper portion of the next following groove and the cam follower pins 296 300 are thus compelled to successively move from one groove to the next the shaft 282 will be intermittently actuated through successive 90 increments of rotary movement in the same rotary direction. It will be noted that each half of every press cycle produces one 90 increment of rotation of shaft 282 and thus cam 280 completes one revolution for consecutive cycles of the press.

A general description of the operation of the apparatus of FIGS. 10-I7 will now be made. REferring initially to FIG. 18 there is shown a timing diagram that is similar to that shown in FIG. 9. Here the time 1, indicates the time when the stem of valve 266 is depressed while time 1 indicates the time that said valve stem is allowed to be restored to its normal position. Cam 280 which is peripherally contoured like cam 96 is fixed in the proper rotative position on shaft 282 to produce this FIG. 18 timing. The cam 280 is arranged so that in the normal upper rest position of the press ram the valve 266 is in its said normal condition wherein the outlet line 267 thereof is connected to exhaust. Under these conditions the condition of the fluid circuit and associated fluid motors will be as follows. In FIG. the piston I84 and feedhead 180 will be moved by said continuous fluid-biasing pressure in the rearward end of cylinder 183 in said feed direction 182 so that feedhead 180 engages said end plate 196, FIG. 10. During this movement of feedhead 180 the stock-gripping bar 220 will be held in a stock-gripping position by the continuous fluid-biasing pressure in the upper portions of the feedhead cylinders 21], 212. In similar fashion the piston 192 and the feedhead 190 will be moved in an indexing direction 181 by the continuous fluidbiasing pressure in the left or forward end of the cylinder 191 so that said feedhead 190 engages the end plate 199, FIG. 10. During this movement of the feedhead 190 the stock-gripping bar 241 is held in a stock-releasing position by the springs 242, 243. Thus the feedhead 180 is normally held in a forward stockgripping position while the feedhead 190 is normally held in a rearward stock-releasing position. When the punch press is set in motion the downward movement 310, FIG. 18 of the press ram will cause the cam 280 to be rotated through a 90 increment of movement, there being no actuation of the valve 266 during this first halfof cycle l as may be seen from FIG. 18. After the punching operation the press ram will move upwardly as indicated at 311 and at a time I, immediately after the punch has been withdrawn from the stock the cam 280 will depress the stem of valve 266 so that fluid pressure will be supplied to the said valve outlet line 267. Under these conditions pistons 213, 214 will be moved upwardly and pistons 233, 234 will be moved downwardly, thus respectively moving the stock-gripping means on feedhead 180 to a stock-releasing position and the stock-gripping means on feedhead 190 to stock-gripping position. Supplying of fluid pressure to the said outlet line 267 will also cause the main pistons 184 and 192 to be moved to the right and left respectively as seen in FIG. 15. Thus during cycle l of operation of the press said feedhead 180 will partake of an indexing stroke in direction 181 while feedhead 190 partakes of a stock-feeding stroke in direction 182 to thereby advance the stock by a predetermined length into the press work station.

In the next cycle 11 of operation of the press the press punch will effect a working operation on the newly positioned stock during the downward movement 312, FIG. 18, thereof, there being no valve actuation during this half cycle. After the punching operation the press punch will move upwardly as indicated at 313 and at a time 1 shortly after the punch has been withdrawn from the stock the cam 280 will allow the stem of valve 266 to be restored to its said normal position wherein the valve outlet line 267 is connected to exhaust. Under these conditions the said downwardly biased pistons 213, 214 and the stock-gripping bar 220 will be moved to stock-gripping position while the said springs 243 and 244 will move pistons 233 and 234 and the stock-gripping bar 241 to stock-releasing position. Connecting said line 267 to exhaust will also cause the forwardly biased piston 184 to move the feedhead 180 in a feed direction 182 and the rearwardly biased piston 192 to move said feedhead 190 in an index direction 181. Thus during cycle II the stock-gripping means are set and the feedhead 180 partakes ofa stock-feeding stroke while the feedhead 190 partakes of an indexing stroke.

every two As will be apparent as the press ram reciprocates through successive cycles the valve 266 will be successively placed in one of its operative conditions during each such cycle so that the feedheads 180, alternately partake of feed strokes so as to intermittently advance the stock into the press work station. As was previously mentioned FIG. 15 shows only one fluid motor on each feedhead however it is to be understood that both of the fluid motors on any given feedhead are constructed and actuated in a similar manner. In the actual wiring for the circuitry of both FIGS. 5 and 15 the lengths ofthe fluid conduit lines from the valve means to the two respectively associated feedheads are preferrably made as closely equal as possible and the lengths of the fluid conduit lines from the valve means to the respectively associated feedhead actuating cylinders are also preferrably made as close to equal as possible; the same applies for the fluid conduit lines between the fluid source and the feedheads respectively associated therewith and between the said source and the respectively associated feedhead-actuating cylinders. In this way the stockgripping means will tend to be operated together and the feedheads will also tend to be actuated together.

In FIG. 19 there is shown a modified embodiment of the control arrangement of FIG. 15. Here the said shaft 282 is provided will two cams 315, 316 each of which is peripherally contoured similar to said cam 96, and which are respectively adapted and arranged to control the operation of two three way valves 317 and 318 that each have the same construction and operation described for valve 92, FIGS. 6 and 7. The two valves 317 and 318 are supplied with fluid pressure in the same manner as are valves 92, 93 respectively, of FIG. 5 and the two output lines 320, 321 of said valves 317,318, respectively, are connected to a fluid circuit that is identical to that illustrated in FIG. 5 for controlling the various fluid motors of the stock feeder of FIGS. 10-13.

The control arrangements illustrated in FIGS. 5, 15, and 19 may each be used in connection with the apparatus of either FIGS. 1-4 or FIGS. 10-13.

Since many changes could be made in the embodiment of the invention particularly described and shown herein without departing from the scope of the invention, it is intended that these embodiments be considered as exemplary and that the invention not be limited except as warranted by the following claims.

What Iclaim is:

I. A high-speed stock-feeding device adapted to intermittently feed stock into a punch press having a reciprocating ram: comprising a frame;

a pair of feedheads reciprocally mounted on said frame;

a stock-gripping means carried by each of said feedheads, each of said stock-gripping means being adapted to be moved between stock-gripping and stock-releasing positions;

fluid motor means for reciprocating said feedheads;

additional fluid motor means for actuating said stockgripping means;

fluid valve means for controlling the supply of fluid pressure to said fluid motor means;

a first cam means for operating said fluid valve means;

actuator means for intermittently actuating said first cam means; said actuator means including a second cam means connected to said first cam means; and

drive means adapted to be operated by the reciprocating movement of said press ram for driving said second cam means so as to thereby impart an intermittent indexing motion to said first cam means that operates said fluid valve means.

2. Apparatus as defined by claim 1 wherein said second cam means includes a rotatable member having camming surfaces formed thereon, and a cam follower member cooperating with said camming surfaces, one of said members being connected to drive said first cam means while the other of said members is connected so as to be operated by said press ram so that the resulting relative movement of said members will intermittently drive said first cam means.

3. Apparatus as defined by claim 2 wherein said rotatable member is formed with a series of interconnected spiral-type grooves each groove being stepped in depth along its length so that said cam follower once traversing a given spiral groove is forced to then traverse the next spiral groove whereby said first cam is intermittently driven in one rotative direction.

4. A stock-feeding device for intermittently advancing stock into the tool station ofa punch press or the like: comprising a frame;

a pair of feedheads reciprocally mounted on said frame for movement in indexing and stock feed directions;

a first stock-gripping means mounted on one of said feedheads and conditionable to grip and release the stock to be fed;

a second stock-gripping means mounted on the other one of said feedheads and conditionable to grip and release said stock;

a first fluid motor means for actuating said feedheads so that the latter effectively reciprocate in l8() phase relation;

a second fluid motor means for actuating said stockgripping means to their respective stock-gripping conditions; and

control means for said first and second fluid motor means for causing said feedheads to alternately partake of stockfeeding strokes, said control means being operated in timed relation to the operation of said punch press whereby said first and second stock-gripping means are actuated to opposite operative conditions while the tool of said punch press is still in said stock and said first and second feedheads are actuated in opposite reciprocating directions just after withdrawal of said tool from said stock.

5. Apparatus as defined by claim 4 wherein said feedheads are mounted in tandem relation on said frame.

6. Apparatus as defined by claim 4 wherein said feedheads are mounted on said frame for movement in side-by-side relation so that said gripping means are adapted to alternately grip opposite side portions of said stock.

7. Apparatus as defined by claim 4 wherein said second fluid motor means includes separate fluid motor means for each of said first and second stock gripping means, and wherein said control means includes valve means for alternately supplying fluid pressure to said separate stockgripping fluid motor means, whereby said first stock-gripping means is moved to a stock-gripping condition and said second stock-gripping means is moved to stock-releasing condition during one cycle of operation of said press and whereby said first stock-gripping means is moved to a stock-releasing condition and said second stock-gripping means is moved to a stock-gripping condition during the next cycle of operation of said press.

8. Apparatus as defined by claim 7 wherein said first fluid motor means includes separate fluid motors for respectively actuating said feedheads, and wherein said control means includes a second valve means for alternately supplying fluid pressure to said fluid motors.

9. Apparatus as defined by claim 8 wherein said control means includes cam means for sequentially operating said valve means in timed relation to the operation of said press.

10. Apparatus as defined by claim 9 wherein said control means further includes linkage means coupled at one operative end thereof so as to be actuated by the punch press ram mechanism and at the other end thereof so as to operate said cam means.

11. A stock-feeding device for intermittently advancing stock into the tool station of a punch press or the like: comprising a frame;

a pair of feedheads reciprocally mounted on said frame for movement in indexing and stock feed directions;

a first stock-gripping means mounted on one of said feedheads and conditionable to grip and release the stock to be fed;

a second stock-gripping means mounted on the other one of said feedheads and conditionable to grip and release said stock;

a first fluid motor means for actuating said feedheads so that the latter effectively reciprocate in phase relation;

a second fluid motor means for actuating said stockgripping means to their respective stock-gripping conditions; and

control means for said first and second fluid motor means for causing said feedheads to alternately partake of stockfeeding strokes, said control means being operated in timed relation to the operation of said punch press and including valve means for controlling the operation of said first and second fluid motor means whereby both of said first and second fluid motor means are actuated just after withdrawal of the punch press tool from the said stock.

12. Apparatus as defined by claim 11 wherein said feedheads are mounted in tandem relation on said framev l3. Apparatus as defined by claim 11 wherein said feedheads are mounted on said frame for movement in side-byside relation so that said gripping means are adapted to alternately grip opposite side portions of said stock.

14. Apparatus as defined by claim 11 wherein said first fluid motor means includes separate fluid motors for respectively actuating said feedheads, and wherein said second fluid motor means includes separate fluid motors for respectively actuating said stock-gripping means.

15. Apparatus as defined by claim 11 wherein said control means includes valve means actuated in response to the operation of the tool drive means of said punch press for controlling the flow of pressure fluid to said first and second fluid motor means.

16. A duplex stock-feeding arrangement for intermittently advancing stock into the work station of a punch press or the like: comprising a frame;

a pair of feed slides each mounted for longitudinal reciprocation on said frame;

a first fluid motor means for operating a first one of said feed slides and including a first piston and cylinder unit that operatively extends in one longitudinal direction;

a second fluid motor means for operating the second one of said feed slides and including a second piston and cylinder unit that operatively extends in the opposite longitudinal direction;

stock-gripping means mounted on each of said feed slides;

a third fluid motor means for actuating said stock-gripping means;

valve means for controlling said fluid motor means; and

actuating means operable in timed relation to the operation of the press for actuating said valve means whereby said feed slides alternately partake of feed strokes.

17. Apparatus as defined by claim 16 wherein said feed slides are both disposed between said piston-cylinder units.

18. Apparatus as defined by claim 17 wherein said feed slides are disposed in tandem relation.

19. Apparatus as defined by claim 17 wherein said feed slides are disposed for movement along substantially parallel paths.

20. Apparatus as defined by claim 16 wherein means are provided for continuously biasing said feed slides in one of the respective directions of movement of each slide.

21. Apparatus as defined by claim 16 wherein said valve means comprises a first valving means for said first and second fluid motor means and a second valving means for said third motor means, and wherein said actuating means includes means for sequentially operating said first and second valving means.

22. Apparatus as defined by claim 16 wherein said actuating means includes cam means, and means for intermittently actuating said cam means in timed relation to the operation of said punch press.

23. Apparatus as defined by claim 16: additionally comprising a common stroke-limiting abutment means that may be adjustably moved from one condition to a second condition '50 that the respective operative feed strokes of said feed slides are thereby changed by equal amounts.

24. A duplex stock-feeding device for intermittently advancing stock into the work station of a punch press or the like; comprising a frame;

a pair of feed slides each mounted on said frame for reciprocation in indexing and stock-feeding directions;

said feed slides being mounted on said frame in side-by-side relation for movement along laterally offset and substantially parallel feed paths;

open-throated stock-gripping means mounted on each of said feed slides, said stock-gripping means being adapted to grip and release opposite side portions of said stock;

it first motor means for actuating said feed slides;

a second motor means for actuating said stock-gripping means;

valve means for controlling said second motor means; and

actuating means operable in timed relation to the operation of the press for actuating said valve means so that said stock-gripping means are alternately operated to stockgripping positions while the press tool is still in the stock whereby said feed slides alternately partake of feed strokes.

25; Apparatus as defined by claim 24: additionally comprising a common stroke limiting abutment means that may be adjustably moved from one condition to a second condition so that the respective operative feed strokes of said feed slides are thereby changed by equal amounts.

26. Apparatus as defined by claim 24 wherein said valve means includes two four-way valves and wherein said actuating means includes means to sequentially operate said fourway valves during each cycle of the press; the actuation of the stock-gripping means occurring before the press tool is withdrawn from the stock.

27. A duplex stock feeder for intermittently advancing stock into a work station: comprising a frame;

a pair of feed slides reciprocably mounted on said frame for movement in indexing and stock feed directions;

a normally fixed abutment means carried by said frame for determining the effective limits of reciprocating movement of said feed slides respectively, said feed slides being respectively adapted to move into and out of contact with said abutment means during reciprocation thereof;

said abutment means including two abutment surfaces which respectively determine the limit of movement of said slides in one of the respective directions of reciprocation of each slide, and further including adjusting means for effectively displacing said surfaces by equal amounts whereby the effective lengths of the feed strokes of said slides may be thereby varied by equal amounts;

stock-gripping means carried by each of said slides;

a first actuating means for reciprocating said slides;

a second actuating means for operating said stock-gripping means; and

control means operable in timed relation with the operation at said work station for controlling the operation of said first and second actuating means whereby said feedheads alternately partake of stock feed strokes.

28. Apparatus as defined by claim 27 wherein said two abutment surfaces are disposed on a common member that is threadedly adjustably mounted on said frame.

29. Apparatus as defined by claim 4 wherein said control means includes a means for controlling said first and second fluid motor means so that said feedheads alternately partake ofa plurality of feed strokes for each cycle of operation of said press.

30. Apparatus as defined by claim 11 wherein said control means includes a means for controlling said first and second fluid motor means so that said feedheads alternately partake ofa plurality of feed strokes for each cycle of operation of said press.

31. A duplex stock-feeding device for intermittently advancing stock into the work station of a punch press or the like: comprising a frame;

a pair of feed slides each mounted on said frame for reciprocation in indexing and feed directions;

stock-gripping means mounted on each of said feed slides;

a first pair of fluid motors for respectively actuating said feed slides;

a second pair of fluid motors for respectively actuating said stock-gripping means;

valve means for controlling the operation of said first pair of fluid motors;

additional valve means controlling operation of said second pair of fluid motors;

actuators for respectively actuating said valve means; and

control means operatively responsive to the motion of the ram of said press for controlling the operation of said actuators whereby said valve means and fluid motors cause said feed slides to alternately partake of stock feed strokes, said control means also being operative to cause said stock-gripping to be alternately displaced to their stock-gripping positions while the tool of said press is still in said stock.

32. Apparatus as defined by claim 31 wherein each fluid motor of said first pair of motors comprises a double-acting cylinder.

33. Apparatus as defined by claim 31 wherein said control means is adapted to cause said actuators to actuate at least a portion of said valve means at different times during each cycle of operation of said press.

34. Apparatus as defined by claim 33 wherein said control means is adapted to cause said gripping means to shift their operative conditions while the tool of said press is in said stock.

35. Apparatus as defined by claim 31 wherein said control means is adapted to cause both of said valve means to be actuated so that operation of both of said first and second pairs of fluid motors is initiated while the tool of said punch press is out of said stock.

36. Apparatus as defined by claim 31 wherein said control means is operatively coupled to said press ram.

37. Apparatus as defined by claim 31 wherein said control means includes a mechanical connection to said press.

38. Apparatus as defined by claim 37 wherein said connection is made to the press ram and intermittently drives said actuators in response to the movement of said ram.

39. Apparatus as defined by claim 32: additionally comprising means for continuously supplying air to one end of each of said first pair of fluid motors.

40. Apparatus as defined by claim 31 wherein each of said valve means comprises three-way valve means.

41. Apparatus as defined by claim 31 wherein said actuators include cam means.

42. Apparatus as defined by claim 31 wherein said control means is adapted to actuate said valve actuators at different times in response to the press rams passing through predetermined different positions along its reciprocating path.

43. Apparatus as defined by claim 31 wherein said control means is adapted to actuate said valve actuators in response to the press ram s passing through one point along its reciprocating path.

44. Apparatus as defined by claim 31: additionally comprising means for continually biasing said feed slides in one direction.

45. Apparatus as defined by claim 31 wherein said control means is adapted to cause all four of said fluid motors to be actuated at times when the tool of said press is considerably below the midpoint of its vertical travel.

46. A high-speed duplex feeder for intermittently advancing stock into the work station of a punch press or the like: comprising a frame;

a pair of feed slides reciprocally mounted on said frame for movement in feed and index directions;

stock-gripping means carried by each of said feed slides,

said stock-gripping means being shiftable between stockgripping and release conditions;

a first drive means for actuating said feed slides so that the latter alternately partake of movement in a stock feed direction;

a second drive means for operating said stock-gripping means so that the latter alternately grip the stock to be fed; and

control means operated in response to the operation of said press for controlling the operation of said first and second drive means so that at least one of said feed slides makes at least one stock-feeding stroke for each cycle of operation ofsaid punch press;

said control means including timing means that cause initiation of said feed strokes of said slides at a time when the ram of said press is nearer to the bottom of its operative stroke than to the top of its said stroke.

47. Apparatus as defined by claim 46 wherein said second drive means comprises a fluid motor means and wherein said control means includes a fluid valve means that is operable to cause initiation of operation of said fluid motor means at a time when the ram of said press is nearer to the bottom of its operative stroke than to the top of its said stroke.

48. Apparatus as defined by claim 47 wherein said first drive means includes a fluid motor means.

49. Apparatus as defined by claim 46 wherein said first drive means includes fluid motor means for displacing said slides in one direction and means for yieldably biasing said slides in the opposite direction. Q

50. A high-speed feeder for intermittently advancing stock into the work station ofa punch press or the like: comprising a pair of opposed cooperating grippers for gripping and feeding the stock to be worked;

actuating means for intermittently displacing said grippers to cause said stock to be intermittently advanced in a stock feed direction;

control means operated in timed relation to the operation of said punch press for controlling said actuating means; said control means including timing means for causing said grippers to initiate their stock-advancing movement at a time when the ram of said press is nearer to the bottom of its operative stroke than to the top of its said stroke. 

1. A high-speed stock-feeding device adapted to intermittently feed stock into a punch press having a reciprocating ram: comprising a frame; a pair of feedheads reciprocally mounted on said frame; a stock-gripping means carried by each of said feedheads, each of said stock-gripping means being adapted to be moved between stock-gripping and stock-releasing positions; fluid motor means for reciprocating said feedheads; additional fluid motor means for actuating said stock-gripping means; fluid valve means for controlling the supply of fluid pressure to said fluid motor means; a first cam means for operating said fluid valve means; actuator means for intermittently actuating said first cam means; said actuator means including a second cam means connected to said first cam means; and drive means adapted to be operated by the reciprocating movement of said press ram for driving said second cam means so as to thereby impart an intermittent indexing motion to said first cam means that operates said fluid valve means.
 2. Apparatus as defined by claim 1 wherein said second cam means includes a rotatable member having camming surfaces formed thereon, and a cam follower member cooperating with said camming surfaces, one of said members being connected to drive said first cam means while the other of said members is connected so as to be operated by said press ram sO that the resulting relative movement of said members will intermittently drive said first cam means.
 3. Apparatus as defined by claim 2 wherein said rotatable member is formed with a series of interconnected spiral-type grooves, each groove being stepped in depth along its length so that said cam follower once traversing a given spiral groove is forced to then traverse the next spiral groove whereby said first cam is intermittently driven in one rotative direction.
 4. A stock-feeding device for intermittently advancing stock into the tool station of a punch press or the like: comprising a frame; a pair of feedheads reciprocally mounted on said frame for movement in indexing and stock feed directions; a first stock-gripping means mounted on one of said feedheads and conditionable to grip and release the stock to be fed; a second stock-gripping means mounted on the other one of said feedheads and conditionable to grip and release said stock; a first fluid motor means for actuating said feedheads so that the latter effectively reciprocate in 180* phase relation; a second fluid motor means for actuating said stock-gripping means to their respective stock-gripping conditions; and control means for said first and second fluid motor means for causing said feedheads to alternately partake of stock-feeding strokes, said control means being operated in timed relation to the operation of said punch press whereby said first and second stock-gripping means are actuated to opposite operative conditions while the tool of said punch press is still in said stock and said first and second feedheads are actuated in opposite reciprocating directions just after withdrawal of said tool from said stock.
 5. Apparatus as defined by claim 4 wherein said feedheads are mounted in tandem relation on said frame.
 6. Apparatus as defined by claim 4 wherein said feedheads are mounted on said frame for movement in side-by-side relation so that said gripping means are adapted to alternately grip opposite side portions of said stock.
 7. Apparatus as defined by claim 4 wherein said second fluid motor means includes separate fluid motor means for each of said first and second stock gripping means, and wherein said control means includes valve means for alternately supplying fluid pressure to said separate stock-gripping fluid motor means, whereby said first stock-gripping means is moved to a stock-gripping condition and said second stock-gripping means is moved to stock-releasing condition during one cycle of operation of said press and whereby said first stock-gripping means is moved to a stock-releasing condition and said second stock-gripping means is moved to a stock-gripping condition during the next cycle of operation of said press.
 8. Apparatus as defined by claim 7 wherein said first fluid motor means includes separate fluid motors for respectively actuating said feedheads, and wherein said control means includes a second valve means for alternately supplying fluid pressure to said fluid motors.
 9. Apparatus as defined by claim 8 wherein said control means includes cam means for sequentially operating said valve means in timed relation to the operation of said press.
 10. Apparatus as defined by claim 9 wherein said control means further includes linkage means coupled at one operative end thereof so as to be actuated by the punch press ram mechanism and at the other end thereof so as to operate said cam means.
 11. A stock-feeding device for intermittently advancing stock into the tool station of a punch press or the like: comprising a frame; a pair of feedheads reciprocally mounted on said frame for movement in indexing and stock feed directions; a first stock-gripping means mounted on one of said feedheads and conditionable to grip and release the stock to be fed; a second stock-gripping means mounted on the other one of said feedheads and conditionable to grip and release said stock; a first fluid motor means for actuating said feedheads so that the latter effectively reciprocate in 180* phase relation; a second fluid motor means for actuating said stock-gripping means to their respective stock-gripping conditions; and control means for said first and second fluid motor means for causing said feedheads to alternately partake of stock-feeding strokes, said control means being operated in timed relation to the operation of said punch press and including valve means for controlling the operation of said first and second fluid motor means whereby both of said first and second fluid motor means are actuated just after withdrawal of the punch press tool from the said stock.
 12. Apparatus as defined by claim 11 wherein said feedheads are mounted in tandem relation on said frame.
 13. Apparatus as defined by claim 11 wherein said feedheads are mounted on said frame for movement in side-by-side relation so that said gripping means are adapted to alternately grip opposite side portions of said stock.
 14. Apparatus as defined by claim 11 wherein said first fluid motor means includes separate fluid motors for respectively actuating said feedheads, and wherein said second fluid motor means includes separate fluid motors for respectively actuating said stock-gripping means.
 15. Apparatus as defined by claim 11 wherein said control means includes valve means actuated in response to the operation of the tool drive means of said punch press for controlling the flow of pressure fluid to said first and second fluid motor means.
 16. A duplex stock-feeding arrangement for intermittently advancing stock into the work station of a punch press or the like: comprising a frame; a pair of feed slides each mounted for longitudinal reciprocation on said frame; a first fluid motor means for operating a first one of said feed slides and including a first piston and cylinder unit that operatively extends in one longitudinal direction; a second fluid motor means for operating the second one of said feed slides and including a second piston and cylinder unit that operatively extends in the opposite longitudinal direction; stock-gripping means mounted on each of said feed slides; a third fluid motor means for actuating said stock-gripping means; valve means for controlling said fluid motor means; and actuating means operable in timed relation to the operation of the press for actuating said valve means whereby said feed slides alternately partake of feed strokes.
 17. Apparatus as defined by claim 16 wherein said feed slides are both disposed between said piston-cylinder units.
 18. Apparatus as defined by claim 17 wherein said feed slides are disposed in tandem relation.
 19. Apparatus as defined by claim 17 wherein said feed slides are disposed for movement along substantially parallel paths.
 20. Apparatus as defined by claim 16 wherein means are provided for continuously biasing said feed slides in one of the respective directions of movement of each slide.
 21. Apparatus as defined by claim 16 wherein said valve means comprises a first valving means for said first and second fluid motor means and a second valving means for said third motor means, and wherein said actuating means includes means for sequentially operating said first and second valving means.
 22. Apparatus as defined by claim 16 wherein said actuating means includes cam means, and means for intermittently actuating said cam means in timed relation to the operation of said punch press.
 23. Apparatus as defined by claim 16: additionally comprising a common stroke-limiting abutment means that may be adjustably moved from one condition to a second condition so that the respective operative feed strokes of said feed slides are thereby changed by equal amounts.
 24. A duplex stock-feeding device for intermittently advancing stock into the work station of a punch press or the like; comprising a frame; a pair of feed slides each mouNted on said frame for reciprocation in indexing and stock-feeding directions; said feed slides being mounted on said frame in side-by-side relation for movement along laterally offset and substantially parallel feed paths; open-throated stock-gripping means mounted on each of said feed slides, said stock-gripping means being adapted to grip and release opposite side portions of said stock; a first motor means for actuating said feed slides; a second motor means for actuating said stock-gripping means; valve means for controlling said second motor means; and actuating means operable in timed relation to the operation of the press for actuating said valve means so that said stock-gripping means are alternately operated to stock-gripping positions while the press tool is still in the stock whereby said feed slides alternately partake of feed strokes.
 25. Apparatus as defined by claim 24: additionally comprising a common stroke limiting abutment means that may be adjustably moved from one condition to a second condition so that the respective operative feed strokes of said feed slides are thereby changed by equal amounts.
 26. Apparatus as defined by claim 24 wherein said valve means includes two four-way valves, and wherein said actuating means includes means to sequentially operate said four-way valves during each cycle of the press; the actuation of the stock-gripping means occurring before the press tool is withdrawn from the stock.
 27. A duplex stock feeder for intermittently advancing stock into a work station: comprising a frame; a pair of feed slides reciprocably mounted on said frame for movement in indexing and stock feed directions; a normally fixed abutment means carried by said frame for determining the effective limits of reciprocating movement of said feed slides respectively, said feed slides being respectively adapted to move into and out of contact with said abutment means during reciprocation thereof; said abutment means including two abutment surfaces which respectively determine the limit of movement of said slides in one of the respective directions of reciprocation of each slide, and further including adjusting means for effectively displacing said surfaces by equal amounts whereby the effective lengths of the feed strokes of said slides may be thereby varied by equal amounts; stock-gripping means carried by each of said slides; a first actuating means for reciprocating said slides; a second actuating means for operating said stock-gripping means; and control means operable in timed relation with the operation at said work station for controlling the operation of said first and second actuating means whereby said feedheads alternately partake of stock feed strokes.
 28. Apparatus as defined by claim 27 wherein said two abutment surfaces are disposed on a common member that is threadedly adjustably mounted on said frame.
 29. Apparatus as defined by claim 4 wherein said control means includes a means for controlling said first and second fluid motor means so that said feedheads alternately partake of a plurality of feed strokes for each cycle of operation of said press.
 30. Apparatus as defined by claim 11 wherein said control means includes a means for controlling said first and second fluid motor means so that said feedheads alternately partake of a plurality of feed strokes for each cycle of operation of said press.
 31. A duplex stock-feeding device for intermittently advancing stock into the work station of a punch press or the like: comprising a frame; a pair of feed slides each mounted on said frame for reciprocation in indexing and feed directions; stock-gripping means mounted on each of said feed slides; a first pair of fluid motors for respectively actuating said feed slides; a second pair of fluid motors for respectively actuating said stock-gripping means; valve means for controlling the operation of said first pair of fluId motors; additional valve means controlling operation of said second pair of fluid motors; actuators for respectively actuating said valve means; and control means operatively responsive to the motion of the ram of said press for controlling the operation of said actuators whereby said valve means and fluid motors cause said feed slides to alternately partake of stock feed strokes, said control means also being operative to cause said stock-gripping to be alternately displaced to their stock-gripping positions while the tool of said press is still in said stock.
 32. Apparatus as defined by claim 31 wherein each fluid motor of said first pair of motors comprises a double-acting cylinder.
 33. Apparatus as defined by claim 31 wherein said control means is adapted to cause said actuators to actuate at least a portion of said valve means at different times during each cycle of operation of said press.
 34. Apparatus as defined by claim 33 wherein said control means is adapted to cause said gripping means to shift their operative conditions while the tool of said press is in said stock.
 35. Apparatus as defined by claim 31 wherein said control means is adapted to cause both of said valve means to be actuated so that operation of both of said first and second pairs of fluid motors is initiated while the tool of said punch press is out of said stock.
 36. Apparatus as defined by claim 31 wherein said control means is operatively coupled to said press ram.
 37. Apparatus as defined by claim 31 wherein said control means includes a mechanical connection to said press.
 38. Apparatus as defined by claim 37 wherein said connection is made to the press ram and intermittently drives said actuators in response to the movement of said ram.
 39. Apparatus as defined by claim 32: additionally comprising means for continuously supplying air to one end of each of said first pair of fluid motors.
 40. Apparatus as defined by claim 31 wherein each of said valve means comprises three-way valve means.
 41. Apparatus as defined by claim 31 wherein said actuators include cam means.
 42. Apparatus as defined by claim 31 wherein said control means is adapted to actuate said valve actuators at different times in response to the press ram''s passing through predetermined different positions along its reciprocating path.
 43. Apparatus as defined by claim 31 wherein said control means is adapted to actuate said valve actuators in response to the press ram''s passing through one point along its reciprocating path.
 44. Apparatus as defined by claim 31: additionally comprising means for continually biasing said feed slides in one direction.
 45. Apparatus as defined by claim 31 wherein said control means is adapted to cause all four of said fluid motors to be actuated at times when the tool of said press is considerably below the midpoint of its vertical travel.
 46. A high-speed duplex feeder for intermittently advancing stock into the work station of a punch press or the like: comprising a frame; a pair of feed slides reciprocally mounted on said frame for movement in feed and index directions; stock-gripping means carried by each of said feed slides, said stock-gripping means being shiftable between stock-gripping and release conditions; a first drive means for actuating said feed slides so that the latter alternately partake of movement in a stock feed direction; a second drive means for operating said stock-gripping means so that the latter alternately grip the stock to be fed; and control means operated in response to the operation of said press for controlling the operation of said first and second drive means so that at least one of said feed slides makes at least one stock-feeding stroke for each cycle of operation of said punch press; said control means including timing means that cause initiation of said feed strokes of said slides at a time when the ram of said press is nearer to the bottom of its operative stRoke than to the top of its said stroke.
 47. Apparatus as defined by claim 46 wherein said second drive means comprises a fluid motor means, and wherein said control means includes a fluid valve means that is operable to cause initiation of operation of said fluid motor means at a time when the ram of said press is nearer to the bottom of its operative stroke than to the top of its said stroke.
 48. Apparatus as defined by claim 47 wherein said first drive means includes a fluid motor means.
 49. Apparatus as defined by claim 46 wherein said first drive means includes fluid motor means for displacing said slides in one direction and means for yieldably biasing said slides in the opposite direction.
 50. A high-speed feeder for intermittently advancing stock into the work station of a punch press or the like: comprising a pair of opposed cooperating grippers for gripping and feeding the stock to be worked; actuating means for intermittently displacing said grippers to cause said stock to be intermittently advanced in a stock feed direction; control means operated in timed relation to the operation of said punch press for controlling said actuating means; said control means including timing means for causing said grippers to initiate their stock-advancing movement at a time when the ram of said press is nearer to the bottom of its operative stroke than to the top of its said stroke. 